/Engine/Source/Runtime/Core/Public/Internationalization/ILocalizedTextSource.h
Given a localization category, get the native culture for the category (if known).
True if the native culture was populated, or false if the native culture is unknown.
bool GetNativeCultureName ( const ELocalizedTextSourceCategory InCategory, [FString](API\Runtime\Core\Containers\FString) & OutNativeCultureName )